Coastal Arrowhead vs Coastal Flat-body

Sagittaria graminea compared with Agonopterix yeatiana

Key Differences

Coastal Arrowhead is Not Evaluated while Coastal Flat-body is Near Threatened.

Taxonomic Classification

Rank	Coastal Arrowhead	Coastal Flat-body
Kingdom	Plantae (Plants)	Animalia (Animals)
Phylum	Magnoliophyta (Flowering Plants)	Arthropoda (Arthropods)
Class	Liliopsida (Monocots)	Insecta (Insects)
Order	Alismatales (Alismatales)	Lepidoptera (Butterflies & Moths)
Family	Alismataceae	Depressariidae
Genus	Sagittaria	Agonopterix
Species	Sagittaria graminea	Agonopterix yeatiana

Conservation Status

Coastal Arrowhead

NE — Not Evaluated

Coastal Flat-body

NT — Near Threatened

Physical Characteristics

Attribute	Coastal Arrowhead	Coastal Flat-body
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Coastal Arrowhead

Habitat

Typically found in grasslands, wetlands, forests, and cultivated landscapes.

Range

Widely distributed across Asia (China, Japan), Europe (6 countries), and North America (United States).

Coastal Flat-body

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, and Sweden. Listed as Near Threatened, this species requires ongoing monitoring to prevent population decline.

Coastal Arrowhead

Sagittaria graminea, the coastal arrowhead or grass-leaved arrowhead, is an aquatic or semi-aquatic perennial herb in the family Alismataceae native to wetland habitats across a wide geographic range including eastern North America, parts of Asia including China and Japan, and isolated populations in Europe. The species inhabits shallow water margins, muddy shores, freshwater marshes, slow-moving streams, ditches, and pond edges, where it often forms dense emergent colonies. Sagittaria graminea is distinguished from other arrowheads by its narrow, grass-like submerged and emergent leaves that lack the pronounced arrowhead shape characteristic of the genus when leaves are fully emergent, though aerial leaves may have small basal lobes. The plant produces white three-petaled flowers arranged in whorls on tall flowering stems, with male flowers above and female flowers below. It is assessed as Not Evaluated by the IUCN. The tubers of arrowheads have historically been consumed as a starchy food by Indigenous peoples across North America. The species provides important habitat structure for aquatic invertebrates and waterfowl, and waterfowl consume the seeds and tubers. The name Sagittaria derives from the Latin for arrow, reflecting the classic arrowhead leaf shape seen in other species of the genus.

Coastal Flat-body

Agonopterix yeatiana, the coastal flat-body, is a small moth in the family Depressariidae native to coastal and calcareous grassland habitats across western and northern Europe, with records from Belgium, Denmark, and Sweden. Moths in the family Depressariidae, commonly called flat-body moths due to the depressed posture they adopt when resting with wings held flat against the surface, are associated predominantly with umbellifer plants of the family Apiaceae as larval hosts. Agonopterix yeatiana larvae feed on wild carrot (Daucus carota), wild parsnip (Pastinaca sativa), and related coastal and grassland Apiaceae species, inhabiting the open, often calcareous or sandy habitats where these plants grow. Adult moths have greyish-brown forewing with a distinctive pattern of spots and dashes and reach approximately 8–12 millimeters in wingspan. The species is classified as Near Threatened by the IUCN, reflecting declines associated with the loss of traditional hay meadow management, coastal grassland degradation, and scrub encroachment that eliminates the open, flower-rich grassland habitats supporting its host plants. Agricultural intensification has reduced wild umbellifer populations significantly across lowland Europe, reducing food resources for larvae of specialist moths like A. yeatiana.